Gradual and rapid shifts in the composition of assemblages of hydroids (Cnidaria) along depth and latitude in the deep Atlantic Ocean

Author(s)

Fernandez, Marina O. ^[1] ; Collins, Allen G. ^[2] ; Marques, Antonio C. ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Biociencias, Dept Zool, Sao Paulo - Brazil

^[2] NOAA, Natl Systemat Lab, Natl Marine Fisheries Serv, Smithsonian Natl Museum Nat Hist, Washington, DC - USA

• Document type: Journal article
• Source: Journal of Biogeography; v. 47, n. 7 APR 2020.
• Web of Science Citations: 0

Abstract

Aim Despite growing knowledge on deep-sea benthic fauna, patterns of changes in species composition combining both bathymetric and latitudinal variation are still poorly known. In the first synthesis on the beta diversity patterns of assemblages of hydroids across an entire ocean basin, our aim was to infer limits and gradients of species distribution along depth and latitude. Location Atlantic Ocean and adjacent polar seas. Taxon Hydrozoa. Methods Hydroids from 50 to 5,330 m deep were studied primarily based on museum collections. Identifications were made by the authors, improving uniformity within the dataset by avoiding variations in taxonomic interpretation. Data totalled 3,699 records belonging to 432 species, at 1,444 unique sites. Records were assigned to three depth strata (50-200, 201-1,000 and 1,001-5,330 m) and eight latitudinal bands of 20 degrees each, totalling 24 sample areas. We conducted non-metric multidimensional scaling (NMDS) ordination, clustering and PERMANOVA analyses of species compositions and abundances per area to examine differences and relationships in hydroid assemblages among areas. Results Assemblages primarily differentiate between those to the north and south of 40 degrees S, regardless of depth, with southern ones separated between Patagonian and Antarctic. Northwards of 40 degrees S, assemblages differentiate gradually along both depth and latitude, although a faunal turnover occurs at 1,000 m deep. Also, assemblages at 1,001-5,330 m deep tend to be more similar to each other than assemblages at shallower strata, suggesting significant connectivity over great distances in the deep sea. We note the problem of largely unequal hydroid sampling in the Atlantic Ocean across depths and latitudes, especially in the southern hemisphere and below 1,000 m deep. Main Conclusions Assemblages of hydroids differentiate gradually along latitude and depth, with more rapid shifts in species composition occurring at 40 degrees S, 60 degrees S and at 1,000 m deep. Greater similarity was found among deeper water assemblages. (AU)

• FAPESP's process: 15/16948-9 - Distribution patterns of hydroids (Cnidaria, Hydrozoa) in deep Atlantic waters and adjacent polar seas
• Grantee: Marina de Oliveira Fernandez
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 18/04257-0 - Deep-sea macroecology: integrating taxonomy, phylogeny, and function into inferences of Atlantic hydroids (Cnidaria) distribution patterns
• Grantee: Marina de Oliveira Fernandez
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 11/50242-5 - Dimensions of marine life: patterns and process of diversifications in planktonic and benthic cnidarians
• Grantee: Antonio Carlos Marques
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants
• FAPESP's process: 13/10821-1 - Distribution patterns of hydrozoans (Cnidaria) in deep waters of the Atlantic Ocean and adjacent polar seas
• Grantee: Marina de Oliveira Fernandez
• Support Opportunities: Scholarships in Brazil - Doctorate